1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 // AudioOutputDispatcherImpl is an implementation of AudioOutputDispatcher. 6 // 7 // To avoid opening and closing audio devices more frequently than necessary, 8 // each dispatcher has a pool of inactive physical streams. A stream is closed 9 // only if it hasn't been used for a certain period of time (specified via the 10 // constructor). 11 // 12 13 #ifndef MEDIA_AUDIO_AUDIO_OUTPUT_DISPATCHER_IMPL_H_ 14 #define MEDIA_AUDIO_AUDIO_OUTPUT_DISPATCHER_IMPL_H_ 15 16 #include <list> 17 #include <map> 18 19 #include "base/basictypes.h" 20 #include "base/memory/ref_counted.h" 21 #include "base/memory/weak_ptr.h" 22 #include "base/timer/timer.h" 23 #include "media/audio/audio_io.h" 24 #include "media/audio/audio_manager.h" 25 #include "media/audio/audio_output_dispatcher.h" 26 #include "media/audio/audio_parameters.h" 27 28 namespace media { 29 30 class AudioOutputProxy; 31 32 class MEDIA_EXPORT AudioOutputDispatcherImpl : public AudioOutputDispatcher { 33 public: 34 // |close_delay_ms| specifies delay after the stream is paused until 35 // the audio device is closed. 36 AudioOutputDispatcherImpl(AudioManager* audio_manager, 37 const AudioParameters& params, 38 const std::string& input_device_id, 39 const base::TimeDelta& close_delay); 40 41 // Opens a new physical stream if there are no pending streams in 42 // |idle_streams_|. Do not call Close() or Stop() if this method fails. 43 virtual bool OpenStream() OVERRIDE; 44 45 // If there are pending streams in |idle_streams_| then it reuses one of 46 // them, otherwise creates a new one. 47 virtual bool StartStream(AudioOutputStream::AudioSourceCallback* callback, 48 AudioOutputProxy* stream_proxy) OVERRIDE; 49 50 // Holds the physical stream temporarily in |pausing_streams_| and then 51 // |stream| is added to the pool of pending streams (i.e. |idle_streams_|). 52 virtual void StopStream(AudioOutputProxy* stream_proxy) OVERRIDE; 53 54 virtual void StreamVolumeSet(AudioOutputProxy* stream_proxy, 55 double volume) OVERRIDE; 56 57 virtual void CloseStream(AudioOutputProxy* stream_proxy) OVERRIDE; 58 59 virtual void Shutdown() OVERRIDE; 60 61 private: 62 typedef std::map<AudioOutputProxy*, AudioOutputStream*> AudioStreamMap; 63 friend class base::RefCountedThreadSafe<AudioOutputDispatcherImpl>; 64 virtual ~AudioOutputDispatcherImpl(); 65 66 friend class AudioOutputProxyTest; 67 68 // Creates a new physical output stream, opens it and pushes to 69 // |idle_streams_|. Returns false if the stream couldn't be created or 70 // opened. 71 bool CreateAndOpenStream(); 72 73 // A task scheduled by StartStream(). Opens a new stream and puts 74 // it in |idle_streams_|. 75 void OpenTask(); 76 77 // Before a stream is reused, it should sit idle for a bit. This task is 78 // called once that time has elapsed. 79 void StopStreamTask(); 80 81 // Called by |close_timer_|. Closes all pending streams. 82 void ClosePendingStreams(); 83 84 base::TimeDelta pause_delay_; 85 size_t paused_proxies_; 86 typedef std::list<AudioOutputStream*> AudioOutputStreamList; 87 AudioOutputStreamList idle_streams_; 88 AudioOutputStreamList pausing_streams_; 89 90 // Used to post delayed tasks to ourselves that we cancel inside Shutdown(). 91 base::WeakPtrFactory<AudioOutputDispatcherImpl> weak_this_; 92 base::DelayTimer<AudioOutputDispatcherImpl> close_timer_; 93 94 AudioStreamMap proxy_to_physical_map_; 95 96 DISALLOW_COPY_AND_ASSIGN(AudioOutputDispatcherImpl); 97 }; 98 99 } // namespace media 100 101 #endif // MEDIA_AUDIO_AUDIO_OUTPUT_DISPATCHER_IMPL_H_ 102